<div style="float: left;"><?php echo __('Model') ?>:</div>
<?php if( !empty($children) ): ?>
    <div style="float: right;"><?php echo select_tag(
                'filters[model_id]'
                , options_for_select(
                    $children
                    , 0
                    , array(
                        'include_custom' => __('Choose')
                    )
                )
                , array(
                    'class' => 'search_input'
                    , 'id' => 'children_list'
                )
            )?>
    </div>
<?php else: ?>
    <div style="float: right;"><select class="search_input" disabled="disabled">
        <option>---</option>
    </select>
    </div>
<?php endif; ?>